PHOENIX -- New courtroom testimony reveals what may have happened the night someone tried to rob an Arizona State University student, and instead, ended up killing her. Kyleigh Sousa was dragged to death more than two years ago when a purse snatcher drove off with Sousa still tangled up in the purse strings.

Joseluis Marquez faces first degree murder charges for the 2010 dragging death of Sousa. He listened quietly as his trial continued with witness testimony from the fateful night.

"I saw her get run over but I didn't think it was so serious," said Nicholas Caudle, who happened to see Sousa get hit and dragged the night of the botched robbery. He called 911 that night. "I thought she had an injury to her leg but when got up onto her she - just - was gone. Her friend was yelling, 'Kyleigh, Kyleigh, Kyleigh,' and there was blood pouring out of her face and she just had a blank look on her face."

One prosecution witness was a man who claims to have been one of four passengers in Marquez's car on the night in question. He identified Marquez as the person who grabbed Sousa's purse and then dragged her for 30 feet outside the IHOP near ASU's Tempe campus.

"I heard her scream and she wouldn't let go and I guess she got ran over," said the prosecution's witness, adding that he didn't realize at the time that Sousa had been dragged and run over. "I honestly thought it was a speed bump."

The witness said it wasn't until months later while he was in prison for an unrelated crime that he went to police after finding out Sousa had died. The defense used this and other foggy witness memories from that night to poke holes in the prosecution's narrative.

"Out of all the photo lineups that [the police] showed you, were you ever able to identify the driver of the vehicle?" the defense asked Caudle.